1. Wireless
Technology
HEM SAGAR POKHREL
LECTURER, PRIME COLLEGE
WiFi

2. INSIDETHISPRESENTATION
Introduction | Wi-Fi Technology
Hotspots
Wi-Fi Network Elements
•Peer to Peer Network
•Infrastructure Network
Wi-Fi Network Topologies
How a Wi-Fi Network Works
WiFi Technology Specifications |
Types
Privacy and Security of WiFi
Basics
Advantages
Limitations

3. Introduction
 Wireless, in general, refers to an alternative to Wired Technology which is
commonly used for connecting devices in wireless(without wires) mode.
 Wireless broadband can deliver fast internet speed by using radio waves
instead of cables or wires.
 Wi-Fi (Wireless Fidelity) is a generic term that refers to IEEE 802.11
standard for Wireless Local Area Networks (WLANs).
 Wi-Fi Network connect computing devices to each other, to the internet
and to the wired network.
 The governing body that owns the term Wi-Fi is the Wi-Fi Alliance which
defines WiFi as any WLAN (wireless local area network) products that are
based on the Institute of Electrical and Electronics Engineers’ (IEEE)
802.11 standards.

4. Governing Body | WiFi Alliance
 Formed in 1999
 Founding Companies of WiFi
Alliance are:
 Nokia
 3Com
 Aironet
 Harris Semi Conductor
 Lucent
 Symbol Technologies

5. Introduction | WiFi
 Main application of WiFi is to provide highly local wireless radio
links to end user communication equipment such as PCs, VoIP
phones etc. within customer premises/residents.
 The latest WiFi products support data rates up to 54 Mbps and
encryption software is used to provide user security.
 WiFi “hotspots” are premises such as airport and restaurants
which have set up local WiFi connectivity to the internet.

6. Hotspots
 A hotspot is a physical location where people may obtain Internet
access, typically using Wi-Fi technology, via a wireless local area
network (WLAN) using a router connected to an internet service
provider. - Wikipedia
 A Hotspot is a geographical area that has a readily accessible wireless
network and equipped with Broad band Internet connection and one
or more Access points that allow users to access the internet wirelessly.
 Hotspots can be setup in any public location that can support an
Internet connection.

7. Elements of a WI-FI Network
 Access Point (AP) - The AP is a wireless LAN transceiver or
“base station” that can connect one or many wireless devices
simultaneously to the Internet.
 Wi-Fi cards - They accept the wireless signal and relay
information. They can be internal and external.
 Safeguards - Firewalls and anti-virus software protect networks
from uninvited users and keep information secure.

8. Wi-Fi Network Topologies
Peer-to-peer
topology (Ad-
hoc Mode)
AP-based
topology
(Infrastructure
Mode)

9. Peer-to-peer topology
 Access Point is not required.
 Client devices within a cell can
communicate with each other
directly.
 It is useful for setting up a wireless
network quickly and easily.
 For e.g. Wi-Fi Direct

10. Infrastructure network
 The client communicate
through Access Point.
 Any communication has
to go through AP.
If a Mobile Station (MS), like a computer, a PDA, or a phone, wants to
communicate with another MS, it needs to send the information to AP
first, then AP sends it to the destination MS.

11. How a Wi-Fi Network Works
 A Wi-Fi hotspot is created by installing an access point to an internet
connection.
 An access point acts as a base station.
 When Wi-Fi enabled device encounters a hotspot the device can then
connect to that network wirelessly.
 A single access point can support up to 30 users and can function
within a range of 100 – 150 feet indoors and up to 300 feet outdoors.
 Many access points can be connected to each other via Ethernet
cables to create a single large network.

12. The Wi-Fi Technology | specifications
 Wi-Fi Networks use Radio Technologies to transmit and
receive data at high speed:
 WiFi Specifications (based on IEEE 802.11x standard)
802.11b
802.11a
802.11g

13. Other specifications
802.11 protocols
Source: Wikipedia

14. IEEE 802.11b
 Introduced in late 1999
 Operates at 2.4GHz radio spectrum.
 Speed
 11 Mbps (theoretical speed) - within 30 m Range
 4-6 Mbps (actual speed)
 Range: 100 -150 feet
 Most popular, Least Expensive
 Interference from mobile phones and Bluetooth
devices which can reduce the transmission
speed.

15. IEEE 802.11a
 Introduced in 2001
 Operates at 5 GHz (less popular)
 Speed:
 54 Mbps (theoretical speed)
 15-20 Mbps (Actual speed)
 Range: 50-75 feet
 More expensive
 Not compatible with 802.11b

16. IEEE 802.11g
 Introduced in 2003
 Combine the best features of both standards
(a, b)
 Speed:
 54 Mbps Speed
 2.4 GHz radio frequencies
 Range: 100-150 feet
 Compatible with 802.11 b

17. Wi-Fi Security
1. Service Set Identifier (SSID)
2. Wired Equivalent Privacy (WEP)
3. Wireless Protected Access (WPA)
4. MAC Address Filtering
5. IEEE 802.11i
 WEP and WPA are encryption protocols that you can choose from in your router's
firmware.
 Wi-Fi Protected Access (WPA), a subset of the newly introduced 802.11i security
standard, is replacing the flawed Wired Equivalent Privacy (WEP).
 Without your SSID, people will not be able to join your Wi-Fi hotspot.

18. WiFi Application Areas
1. Turn Your Smartphone into a Remote Control
2. Send Documents to Your Printer from Any Computer or Smartphone
3. Forward Notifications from Your Smartphone to Your PC
4. Tether Your Smartphone to Your Computer for Internet Anywhere
5. Stream Movies to Any TV in the House
6. Share Files with Nearby Computers
7. Stream Audio to Any Speakers in the House
8. Wirelessly Transfer Photos from Your Digital Camera
9. Tell Your Phone When Its Home (or Not)
10. Sync Your Music Library, Photo Library, or Other Files with Your Smartphone
USB-Free
Source: Lifehacker.com

19. WiFi Advantages
 Mobility : Allows users to freely move while using internet.
 Ease of Installation
 Flexibility: new nodes can be easily added.
 Cost : No need of wires and cables
 Reliability
 Security
 Use unlicensed part of the radio spectrum
 Speed

20. Other Advantages
 Many electronic devices use Wi-Fi due to its simple
functions.
 Companies use Wi-Fi to create wireless networks
within their boundary.
 Phone companies such as use Wi-Fi Hot Spots for
their users to get free calling/internet access.
 Gaming companies like Nintendo use Wi-Fi to synch
their products and to use global network usage.
 Can be used in place where cables are not
appropriate such as historic buildings and museums.
 Can be installed where ADSL and cable are not
available.

21. Limitations/Drawbacks
 Degradation in performance
 High power consumption
 Limited range
 Interference: Bandwidth can be limited as WiFi
shares airwaves with devices such as microwave
and cordless phones, which can use up valuable
bandwidth.
 Potential security risk: Hackers and Unsecured
WiFi.

22. Finally
 Wi-Fi is being a popular, simple and cost effective way
to connect to internet without using any wires.
 WiFi technology is growing it’s popularity because of
it’s decreasing costs and the freedom it gives to users.

23. Thanking You !!!
Hem Sagar Pokhrel
Faculty Member
Computer science & IT Department
Prime College –Kathmandu, Nepal
E-mail: geeksagar@prime.edu.np
Facebook: www.facebook.com/geeksagar
Twitter: www.twitter.com/nepalisagar
LinkedIn: np.linkedin.com/in/geeksagar